(USA Today) -- The aftershocks of the holiday Fifty Shades of Grey casting bombshell continued to rumble Tuesday, with fans of the erotic bestseller voicing anger (and some love) about the announcement.

Producer Dana Brunetti devoted much of his Twitter page to fans, allowing them to vent or rejoice about the lead characters announced over the Labor Day holiday -- Dakota Johnson as Anastasia Steele and Charlie Hunnam as billionaire Christian Grey.

Brunetti retweeted one fan who compared the casting announcement to the national outcry over casting Ben Affleck as Batman.

"@DanaBrunetti knows how @BenAffleck feels today," the tweet said.

Brunetti went on to post several of the rabid responses he received -- including one that called him "an idiot" for the castings, another that said he would have cast a "monkey" for Grey and one that said, "I hate you. #NoMattNoAlexisNoMovie."

"It's been intense," says Erik Davis a contributing editor for the movie ticketing website Fandango.com of the casting furor. "Whenever you have a property with a rabid fan base like this book, you're going to get these very divisive results. People are not going to like your choices, because you simply made a choice."

Davis believes the fans have responded in this way because they were set on one of the perceived frontrunners discussed so widely on the internet in recent months -- including Man of Steel's Henry Cavill and White Collar star Matt Bomer as Christian Grey.

Author Bret Easton Ellis threw gasoline onto the Twitter-sphere firestorm by invoking Twilight superstar Robert Pattinson. Ellis claimed he had spoken to Fifty Shades of Grey author E L James "at a party over the summer."

"Her first choice for Christian was Rob Pattinson," Ellis tweeted.

Melanie Griffith even joined in the fray, taking one Twitter follower to task who criticized her daughter's looks and the casting decision.

"Wow! You're quite the b---- aren't you? #dontmesswithmama."

Filmmakers and distributor Focus Features have kept a tight lid on who was actually in the running for the parts and have declined further comment on the matter. But Brunetti tried to explain, in general terms, that not everyone was going to be happy with the selection.

"There is a lot that goes into casting that isn't just looks. Talent, availability, their desire to do it, chemistry with other actor, etc," Brunetti noted on Twitter. "So if your favorite wasn't cast, then it is most likely due to something on that list. Keep that in mind while hating and keep perspective."

Beyond not getting the person many fans were hoping for, both Johnson and Hunnam are unknown quantities. Johnson, the model-turned-actress daughter of Melanie Griffith and Don Johnson, is best known for her role in the canceled sitcom Ben and Kate and a brief role in The Social Network. Hunnam is better known for his roles in Pacific Rim and the FX series Sons of Anarchy.

"But they are far from household names. And I think a lot of negativity is because the fans are not familar with these actors," says Davis. "But I love this casting, it gives us all a chance to discover these actors."

After all, Davis recalls the furor over 2008's Twilight casting with then-unknowns Robert Pattinson and Kristen Stewart in the leads.

"I was watching these people and many were rabidly against this," says Davis. "And then look what happened. Pattinson and Stewart turned into superstars. People forget that they didn't like the casting originally."

What's key is the chemistry between the actors on the screen when the movie opens on August 1, 2014. And clearly there was chemistry for E L James, who is one of the producers on the movie, to support the casting.

It was James' Monday announcement that started the furor. As it raged, James made one further comment.

"To all the supporters, lovers and haters -- thank you so much for the passion that you have for this project," James tweeted. "You all rock. All of you."